The present disclosure relates to an idler gear assembly, and more particularly to a generator idler gear assembly.
Integrated drive generators and other generators incorporate journal bearings to support idler gear shafts. The housing supporting the journal bearings are typically constructed from magnesium and the journal bearings are typically constructed from either bronze or carbon/graphite material. Due to the difference in thermal expansion coefficients between the housing and the bearing materials, an anti-rotation feature is typically used to affix the bearings to the housing.
In one example, a cup-shaped aluminum intermediate housing carries one of the journal bearings and is secured to the magnesium housing. The opposite journal bearing is press fit into the magnesium housing. A Belleville washer is arranged between the journal bearing and a cover, which is secured to the intermediate housing. The Belleville washer seats the journal bearing in the intermediate housing bore and exerts sufficient axial force on the journal bearing to prevent rotation and provides axial retention of the journal bearing within the intermediate housing. In another example, an outer diameter of the journal bearing is knurled to better maintain its press fit and provide an anti-rotation feature throughout the generator operating temperature range of −65° F.-400° F. (54° C.-204° C.). The knurl feature also provides axial retention. Employing additional structures and machining to retain the journal bearings in their bores adds complexity and cost to the idler gear assembly.